ἀποκυμβάω
From LSJ
ἀναγκαίως δ' ἔχει βίον θερίζειν ὥστε κάρπιμον στάχυν, καὶ τὸν μὲν εἶναι, τὸν δὲ μή → But it is our inevitable lot to harvest life like a fruitful crop, for one of us to live, one not. (Euripides, Hypsipyle fr. 60.94ff.)
Spanish (DGE)
precipitarse en, tirarse de cabeza εἰς τὸ ὕδωρ Clearch.101 (var.).